In the production of a thin-film semiconductor device in which an organic semiconductor thin film is used such as an organic thin-film transistor (organic TFT), the film-formation of the organic semiconductor thin film to which coating and printing processes are applied is possible. For example, a solution in which an organic semiconductor material has been dissolved in a solvent is coated on a substrate and dried to thereby obtain an organic semiconductor thin film composed of a single-component organic semiconductor material. Thus, an increase in the size of substrates and a decrease in the production cost can be achieved compared with a semiconductor device in which conventional inorganic semiconductor materials such as silicon (Si) are used. Furthermore, since coating and printing processes and the like have low process temperature, formation on plastic substrates is possible and semiconductor devices having flexibility are also expected. As such an example, it has been reported that a backplane in which an organic TFT is provided on a plastic substrate is produced and a flat-panel type display apparatus such as a liquid-crystal display apparatus or an OLED display apparatus is produced with the backplane.
As for materials for constituting organic semiconductor thin films, various materials such as polythiophene, pentacene, and rubrene have been under study. It has been reported that there is a material that has a mobility equal to or more than that of a thin-film semiconductor device in which a semiconductor thin film composed of amorphous silicon is used (for example, refer to Non-Patent Document (“Applied Physics Letters”, {HYPERLINK “http://scitation.aip.org/dbt/dbt.jsp?KEY=APPLAB&Volume=69”, Volume 69}, Issue 26, 1996, p. 4108-4110)).